156 Mr. Cleaveland’s account of fossil shells. 
be of ancient or modern date; whether they were produced by great 
convulsions and sudden inundations, or by gradual alterations of 
many successiye years. It has been suggested that important advan- - 
tages would result from possessing a geographical map, indicating the 
different species of fossil shells, and the places, in which they were 
found, ‘T think the idea important, and practicable at least with re- 
gard to any country or coast, which may be thickly inhabited. 
With such a map before us we should be better enabled to compare 
individual facts, and hence to draw several conclusions. Under this 
view of the subject the discovery of shells, which are merely fluviatile, 
will be worthy of attention. For the preceding reasons I have en- 
deayoured to collect all the facts in my power. I will now give you 
a description of two wells, which I have examined. the last summer, 
while digging. 7 hone Cro aerate See rho gs : 
_ One is in Bowdoin, at the distance of three or four miles from the 
nearest salt water, which is at the termination of the tide in Cathance 
river ; the distance of the well from the sea is probably about twenty 
miles. Its elevation above the tide in Cathance river is estimated by 
gentlemen, living in that part of the country, at seventy or eighty 
‘feet. The land about the well is very uneven, and abounds with 
gneiss and a coarse granite. A small stream passes about fifty rods 
from the well; and, after a long and ‘winding course, assists in form- 
ing the Cathance. — This well is twenty feet deep. Through the first 
ten feet from the surface a hard gravel is found, stratified and inter- 
spersed with layers of coarsé, yellowish sand. At the depth of ten feet 
commences a stratum of blue clay, into which the workmen dug 
7 
ten feet, but without passing through the clay, When first taken 
from the ground, it is nearly black, and yery tenacious. This clay 
both in appearance and-smell resembles that dig on flats, or near salt 
Marshes, or on the margin of salt water rivers, The shells also have. 
